If you already know how to read a web address or URL (Universal Resource Locator, pronounced “you are ell”), skip this section. Otherwise, consider the web address http://www.googleguide.com/searchEngines/google/searchLeader.html. Here’s what it all means:

http

transfer protocol (type of information being transferred)

www.googleguide.com

website name, host name

googleguide

second-level domain name

com

top-level domain name

searchEngines

directory name (major category)

google

sub-directory name (sub-category)

searchLeader

file name (a file within the directory)

html

file format

Here’s a list of some common top-level domain names. Note that some sites don’t follow these conventions:

.edu

educational site (usually a university or college)

.com

commercial business site

.gov

U.S. government/non-military site

.mil

U.S. military sites or agencies

.net

networks, Internet service providers, organizations

.org

non-profit organizations and others

Because the Internet was created in the United States, “US” was not originally assigned to U.S. domain names; however, it’s used to designate American state and local government hosts, including many public schools, and commercial entities, e.g., well.sf.ca.us. The domain .ca represents Canada, unless it’s followed by .us, in which case it represents California.

Domain Codes

State

.ca.us

California

.nv.us

Nevada

.tx.us

Texas

Other countries have their own two letter codes as the top level of their domain names — although many non-US sites use other top-level domains (such as .com):

Domain Codes

Country

.ca

Canada

.de

Germany

.dk

Denmark

.jp

Japan

.il

Israel

.uk

United Kingdom

.za

South Africa

To limit results to a single site or domain, specify the site name (e.g., www.googleguide.com or googleguide.com) or a top-level domain name (e.g., .com or .edu) in Google’s domain selector.